add CI and missing dep on crunch

.gitlab-ci.yml

+stages:
+  - build
+  - image
+  - deploy
+
+# Define some conditions to run the whole pipeline
+workflow:
+  rules:
+    - if: $CI_MERGE_REQUEST_ID                     # Run on MRs
+    - if: $CI_COMMIT_TAG                           # Run on tags
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH  # Run on master
+
+# Customize the build rules and the artifacts here. You probably want to adjust
+# "opam.locked"
+# We define a cache in order to keep the switch with the dependencies installed,
+# unless the opam.locked file has changed.
+build:
+  stage: build
+  image: debian:buster
+  before_script:
+    - apt update
+    - apt install -yqq --no-install-recommends ca-certificates curl opam git pkg-config m4
+    - opam init --disable-sandboxing --bare -ya
+    - opam switch create ocaml-base-compiler.4.12.0
+    - eval "$(opam env)"
+    - opam pin add . -y --no-action
+    - opam install opam-depext
+    - opam depext -y osh
+    - opam install ./*.opam -y --deps-only --with-test --with-doc
+  script:
+    - opam exec -- dune build --profile release @all
+    - opam exec -- dune runtest
+    - mv _build/default/src/server.exe .
+  artifacts:
+    paths:
+      - server.exe
+
+include:
+  - project: 'OCamlPro/gitlab-deployments'
+    ref: master
+    file: deploy.yml
+
+# Builds and pushes the Docker image using Kaniko
+make-image:
+  extends: .make-image  # defined in deploy.yml
+  variables:
+    DOCKERFILE: /kaniko/Dockerfile
+    # don't need a local 'git clone'
+    GIT_STRATEGY: "none"
+  before_script:
+    # Write the Dockerfile for the image we want to generate
+    # Here we inherit from nginx and just add the contents of our web-app
+    - |
+      echo "\
+      FROM bitnami/nginx:latest
+      ADD server.exe /opt/bitnami/nginx/sbin/nginx
+      USER 0
+      RUN apt update && apt install -yqq libev4
+      USER 1001
+      " > $DOCKERFILE
+
+# Deployments are pre-defined in the "dev" environment; they will be stopped
+# after 3 days unless they are on the default branch (master).
+
+# To define production deployments, ensure the domain name is correct, and set
+# the corresponding DNS record as "CNAME" to "a.ocaml.pro"
+deploy-prod:
+  extends: .deploy-prod
+  variables:
+    PUBLIC_HOST: osh.ocamlpro.com

dune-project

@@ -28,6 +28,8 @@
    (>= 1.0.0~alpha2))
   (ocb
    (>= 0.1))
+  (crunch
+   (>= 3.2.0))
   (bisect_ppx
    (and
     :with-test

osh.opam

@@ -13,6 +13,7 @@ depends: [
   "ocaml" {>= "4.08"}
   "dream" {>= "1.0.0~alpha2"}
   "ocb" {>= "0.1"}
+  "crunch" {>= "3.2.0"}
   "bisect_ppx" {with-test & >= "2.6" & dev}
   "odoc" {with-doc}
 ]